High wattage quartz halogen lamp



United States Patent Inventor Carl L. Peterson Gloucester, Massachusetts Appl. No. 783,517 Filed Dec. 13, 1968 Patented Dec. 1, 1970 Assignee Sylvania Electric Products Inc.

a corporation of Delaware HIGH WATTAGE QUARTZ HALOGEN LAMP 8 Claims, 1 Drawing Fig.

U.S. Cl. 313/278, 313/222, 313/273, 313/276, 313/315 Int. Cl. H011: l/l8, H011: 1/56 Field ofSearch 313/222,

[56] References Cited UNITED STATES PATENTS 1,613,791 1/1927 Forrester 3 l 3/278X- 3,445,713 5/1969 Cardwell, Jr. 313/273 Primary Examiner-Raymond F. l-lossfeld AnomeysNorman J. OMalley and James Theodosopoulos ABSTRACT: A quartz halogen lamp has a folded coiled tungsten filament supported on a bridge, the bridge being made of tungsten rods and quartz tubing. Tungsten support wires extend through holes in the wall of the quartz tubing and support each fold of the filament. The support wires are shaped so as to pennit adjustment thereof, when the filament is mounted on the bridge, to provide adequate support for each fold of the filament.

Patented Dec. 1, 1970 w m T E N T E E V P N I L R A C AGENT HIGH WATTAGE QUARTZ HALOGEN LAMP BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to high wattage quartz halogen lamps and particularly to quartz filament mounts of such single ended lamps. More specifically, it pertains to the support of a folded coiled filament in such'mounts.

2. Description of the Prior Art Quartz halogen lamps have become increasingly useful in" lighting applications because of their higher efficiency, better maintenance and smaller size in comparison to' prior art incandescent lamps. As a result of this commercial success,'quartz halogen lamps are being developed with higher power ratings. These lamps are necessarily larger and presentsome problems that are not usually encountered with prior art incandescent lamps or lower wattage quartz halogen lamps. .One problem involves a quartz to metal seal that can satisfactorily handle larger amounts of electric current." In a copending U.S. Pat. application, Ser. No. 596,908 Method of Sealing Quartz to Metal and Device, filed on'Nov. 25, 1966 by Gates et al., and assigned to the assignee of the instant invention, andnow abandoned a lamp is shown which has an improved seal capable of handling increased current.

Another problem concerns the adequacy of the support of the mount at the end opposite the lamp'base, theseal of which is sometimes the only support for theimount; A copending U.S. Pat. application Ser. No. 680,893, Incandescent Lamp, filed on Nov. 6, 1967 bythe instant inventor now Pat. No.

3,497,752 shows an improved mount for such lamps. However in that application, the filament is supported only at the ends thereof, and thus can be supported directly by the tungsten lead-in wires.

The instant application, however, concerns" a foldedfilament which must be supported at other points thereof intermediate the filament legs and preferably at the filament folds.

.The fold support wirescannot be directly connected to the In addition, the corrosive effect of halogen, especially at the high temperatures at which lamps of this type operate, severely limits the materials that can be used within a quartz halogen lamp envelope. Generally, only tungsten and quartz are suita ble. In lower wattage lamps, the filament can be welded or hot crimped to the lead-in wire. But, mainly'because of the increased wire sizes required, such connections are not usually satisfactory in higher wattage lamps.

SUMMARY OF THE'INVENTION This invention discloses a quartz halogen lamp having a bridge which materially stabilizes the central positioningof'a folded coiled filament mounted thereon. The bridge comprises quartz tubing supported by tungsten rods. Tungsten support wires, inserted through substantially diametral holes in the quartz tubing and supported thereby, insulatively'sup port the filament at the folds'thereof. The support wires'have sufficient flexibility and adjustability to conveniently-permit the takeup of any slack between the qusrtztubing and the individual filament folds when the filament is mounted on the bridge. More specifically, one end of the support wire extends through a diametral hole-in the quartz tubing and is bent therearound. The opposite end of the support wire extends through and engages a fold of the filament. Between its ends the support wire has a substantially U-shaped loop, the loop having sufficient flexibility to permit the legs of the U to be squeezed together. Thus when the filament is mounted on the bridge, any slack in the filament can be taken up by squeezing the U-shaped loops of the support wires.

In some cases, it may be desirable to continue the end of the supportwire that engages the filament fold back through the diametral hole in the quartz tubing. Thus, both ends of the support wire extend through the diametral hole and there is effectively a double wire supporting each filament fold. Such a construction can improve the resistance of the filament to sagging, especially when the lamp is operated in a horizontal position. I

Preferably the quartz tubing has slots at each end for the purpose of engaging the above-mentioned tungsten rods and to prevent rotation thereof, said rods also being the lead-in members forthe' lamp. Of course, the rods must have suffrcient rigidity topermit take up of filament slack without deflection and to' adequately support the filament mounted bridge. Preferably, also, electrical connection is established between the rod and the filamentby a compressive connecter coil of the type shown in Ser. No. 680,893. Said coil constrictively encircles thelead-in rod andan abutting portion of the filament leg.

BRIEF DESCRIPTION OF THE DRAWING 'The single FIG. is a perspective view of a high-wattage quartz halogen lamp in accordance with this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT In an example of a 10,000-watt lamp made in accordance with this invention, tubular envelope 1 was made of quartz and was 3 inches diameter by 7% inches long. Lead-in members 2 and 3 were tungsten rods, l25-mils diameter, and were supported in cylindrical quartz to metal seals 14 at the base 15 of the lamp and extended into the interior of envelope 1, generally in parallel. Rods 2 and 3 were about seven-eighth qinch apart'at the base end of the lamp and about 2% inches apart at the filament mount portion thereof. The upper ends of rods 2' and3itenninated about 1% inches from the upper end of envelope]. Disposed between and supported by the upper ends of rods 2 and .3 was'quartz tubing 4. Tubing 4 was 2% inches long byfive-sixteenth inch outside diameter and had a wall thickness of one-sixteenth inch. Each end of tubing 4 had a vertical slot therein, five thirty-seconds inch wide by threesixteenth inch long. The upper ends of rods 2 and 3 were bent into a right angle and had terminal portions about one-fourth inch long extending toward each other. Said terminal portions were disposed within the bare of tubing 4 and the adjacent bent portions of rods 2 and 3 fit into'said slots tubing 4 and the adjacent bent portions of rods 2 and 3 fit into said slots.

Quartz tubing 5 was substantially similar to tubing 4 and was I supported between rods 2 and 3 at a point about 3% inches vertical slots at the ends thereof, the slots being the same size below tubing 4. Tubing 5 was parallel to tubing 4 and also had as those of tubing 4. However, only vertical portions of rods 2 and '3 fit into said'slots. Tubing'S was prevented from movement either'upward or downward on'rods 2 and 3 by compressections. There were three such loops at the upper part of filament 7 and four at the lower part.

Each loop 8 was supported, and maintained slightly in tension, by a support wire 9, extending from the adjacent quartz tubing to the loop. Each support wire 9 was made of a single length of 30-mil tungsten wire. Each support wire 9 extended alinement with its respective loop 8, was folded around said loop, doubled back through said hole and was bent securely around the quartz tubing. One side of support wire Q had a U- shaped loop 10, about 7% inch long by three-sixteenth inch wide. At the time of mounting filament 7, each loop 10 could be squeezed to draw up any slack on filament 7 between tubings 4 and 5.

Legs 12 of filament 7 extended from the upper ends of the outer coiled sections thereof, and were bent so that portions thereof abutted and were parallel to rods 2 and 3, respectively, at a point about one-half inch below tubing 4. Compressive coils l3, encircling leg 12 and the respective rod, provided a secure electrical connection there'between.

The sections of rods 2 and 3 that were in closest proximity to the outer coiled sections of filament 7 were bent at the center thereof to an angle of about 135, the purpose being to increase the spacing therebetween and thus to reduce the cooling effect of the rods on the filament.

At assembly of the filament mount, coils 6 were first inserted on preshaped rods 2 and 3. The external ends of rods 2 and 3 were then clamped in a suitable holding device and coils 13 were inserted on the rods. Filament 7 was then assembled on tubings 4 and by means of support wires 9 and tubings 4 and 5 were then mounted on rods 2 and 3. Rods 2 and 3 had sufficient flexibility to be spread apart enough for the mount-' ing of tubings 4 and 5 thereon. Legs 12 of filament 7 were then connected to their respective rod by means of coil 13. Filament 7 was then centrally positioned in the bridge and loops of support wires 9 were squeezed, where necessary, to take up slack in filament 7.

Rods 2 and 3 were then brazed to seals 14 which had been previously sealed to quartz base 15. The filament mount was then carefully inserted into envelope 1 and base 15 was scaled to the envelope. Protruding arms of coils 6 and 13 pressed slightly against the inside wall of envelope 1 to improve the support of the filament mount and to increase slightly the constriction of the coils.

Envelope 1 was then exhausted through an exhaust tube situated at the upper end thereof, filled with a gas including halogen and sealed.

lclaim: 1

l. A quartz halogen lamp comprising: a tubular envelope having a lamp filling and a base; tungsten lead-in rods extending through said base into the interior of said envelope; a bridge of quartz tubing within said envelope supported by said rods, said tubing having slots at the ends thereof and said rods fitting into said slots; and a planar filament, electrically connected to said lead-in rods, supported by said bridge.

2. The lamp of claim 1 comprising, in addition, tungsten support wires extending through diametral holes in said quartz tubing and supportingsaid filament.

3. The lamp of claim 2 wherein said support wires include a takeup loop.

4. The lamp of claim 3 wherein said support wires fold back so that both ends of each support wire extend through said diametral holes.

5. The lamp of claim 1 wherein a leg of said filament abuts one of said lead-in rods and connection therebetween is established by a separate encircling compressive coil.

6. The lamp of claim 1 wherein the upper ends of said leadin rods are bent toward each other and extend into the bore of said quartz tubing.

7. The lamp of claim 1 wherein said bridge of quartz tubing comprises an upper tubingand a lower tubing and compressive coils encircle said lead-in rods and abut said lower quartz tubing, thereby substantially preventing movement of said lower quartz tubing on said rods.

8. A quartz halogen lamp comprising: a tubular envelope having a lamp filling and having quartz to metal seals at one end thereof; tungsten lead-in rods extending through said seals into the interior of said envelope; a bridge of quartz tubing within said envelope supported by said rods; a planar filament within said envelope electrically connected to said lead-in rods, said filament being supported by means of tungsten support wires extending through diametral holes in said quartz tubing. 

